Vegetable oh



Patented Oct. 21, 1941 VEGETABLE 01L Wells W. Ginn, Cincinnati, Ohio,assignor to Vegetable Oils Specialty Corporation, Cincinnati, Ohio, acorporation of Ohio N 0 Drawing. Application July 18, 1938, Serial No.219,834

5 Claims.

invention relates to vegetable oils and the improvement of them. It isdirected generally to the varnish and printing ink industries, and hasapplication, particularly, to the production of varnishes, printinginks, coating compositions, and the like.

The typical vegetable oils used for such purposes -are linseed oil,China-wood oil, Perilla oil, soybean oil and some others such asoiticica, rapeseed and sesame. In the raw state the oils are in liquidcondition, but they are not sufficiently pure to be used directly, sothey are refined and purified by acid and alkali and decolorizingtreatments. These oils are called varnish oils in the industry, and forconvenience the same terminology is employed in the followingspecification and claims.

Some of the vegetable oils dry or oxidize and polymerize upon exposureto the atmosphere more quickly than the others and for this reason, thevegetable oils are classified generally as drying oils, semi-drying oilsand non-drying oils. The varnish oils .are all of the drying oil andsemi-drying type, and all of these possess the capacity to be bodied andpolymerized upon prolonged heating at elevated temperature.

In general, the varnishoil-s are made into varnishes by heating them toa temperature of 450-600 F. and cooking them at this temperature for asubstantial period of time, as for instance, an hour-in the case ofChina-wood oil, and five to six hours, or more, in the case of linseed,depending upon the consistency desired.

China-wood oil is peculiar in that it bodies very much-faster than theother oils and also in that it provides varnish films which generallyare superior in toughness, durability and moistureproofness. For thesereasons China-wood oil is employed in the industry quite extensively inpreference to the other-oils. However, this oil is quite expensive andthe supply of it is dependent upon foreign sources; the prices fluctuatewidely, inaccordance with general economic, trade and social conditions.In some cases resins are cooked with the oils to increase their filmforming capacity, and in other cases, the oils are bodied first and theresins are added at a later period. The technique depends upon the oilsand resins used and the type of varnish desired.

When the varnish oils are cooked in the varnish kettles the acid valueof them is increased and the iodine value is decreased. In general, itis highly useful for the varnish makers to be able to control .the acidvalue and iodine values of the oils, since these serve as a guideindicating the properties of the resultant varnishes, other factorsbeing equal. But the varnish makers have not been able, up to thepresent time, to control these values the way they have wanted to,except by special 'manipulations which are useful only in specificinstances, or by the addition of foreign materials, such as rosin, lime,driers, and fatty acids of the vegetable oils. 1

The change which takes place in an oil when it is .heated andpolymerized is a complex chemical change, of which little is known orunder stood. For this reason, and because of the inability to controlthe acid and iodine values, the results, in the manufacture of thecoating compositions, havebeen dependent largely upon the artisan skill*of the varnish cooker-s. A primaryobjective of the present inventionhas been to provide a process for controlling the various chemicalchanges which take place in an -oil when it is being cooked to convertit into a varnish. In other words, a process has been sought, and thepresent invention provides the means enabling the varnish makers tocontrol acid andiodine values of varnishes and ink vehicles during theirpolymerization, so that the final products may'have the desiredcharacteristics.

.It has been another objective to shorten the time required. forcooking. A reduction in 'cooking time is important because the longer anoil is cooked the more it tends to become discolored and the more itsacid value'is increased. Dark colored varnishes andvehicles areundesirable for many reasons. The objective has been to provide aprocess .in which linseed, Perilla, soybean and similar oils which mustbe cooked anywhere -from five to eight hours at present, can be bodiedand polymerized in an hour or two.

In further respect, the various vegetable oils possess differentqualities and value by virtue of the differences between the oilsthemselves and the way they are treated and cooked. Some of thevarnishes provide'films which are very much better than others. Forexample, China-wood oil provides tougher, more durable, and moremoisture resilient film than soybean oil -or linseed. On the other hand,the oils which provide these better varnishes are more expensive thanthe others and, consequently, the varnishes are costlier. iIt has beenthe objective in this invention to provide means for obtaining varnishesfrom the less costly oils, such as linseed, soybean and even cottonseed,which are equally as good as the varnishes and vehicles produced I fromthe more expensive oils which heretofore have been used.

Briefly, the present invention is a relatively simple one though thephenomena upon which it is predicated are very complex and difficult toexplain. Castor oil has occupied a peculiar position in the coatingcomposition industries. It has been used as a plasticizer to softenlacquer which otherwise would be brittle. Because of its peculiarchemical properties and its non-drying qualities, it has never been usedin the formulation of varnishes and ink vehicles, and, in fact,

its use has always been specifically avoidedbecause the presence of itprevents the drying of varnish films.

This invention, however, is predicated upon the discovery that when thevarnish oils are cooked in the presence of a small quantityof castoroil, the varnish oils become bodied in onehalf to one-quarter of thetime otherwise required for producing the heavier bodies, the filmforming properties of the resulting varnishes are improved, and the acidvalue and iodine value are directly controllable in relation 'to theamounts of castor oil employed.

When the vegetable oils are cooked in the presence of relatively smallquantities of castor oil, as for example, less than 1%,then,paradoxically, the acid value may be held atneutral or any given value(or may be decreased if other acids are present) during the cooking andthe iodine value is increased, until the influence of the castor oil isexhausted. In other Words, the changes which take place in the iodineand acid values of the varnish oil being cooked in the presence of thecastor oil are diametrically o-pposite to the changes which would takeplace in its absence. The varnish is cooked to a given body in anywherefrom one-half to one-fourth the time otherwise required. 'The filmswhich these varnishes and coating compositions provide are much moredurable, resistant to moisture and much tougher than the films whichotherwise would be produced.

In relation to its various aspects, therefore, the invention provides ameans for controlling the acid or iodine values of a given oil, wherebyany desired acid value is obtained for any given body, in respect tofinal quality; the means for providing better varnishes and film formingvehicles from the inferior vegetable oils, in respect to thesubstitution of one oil for another and in respect to the production ofgood varnishes at low cost; and the means for shortening the time ofcooking in relation to the production of the varnishes.

For the most part, the chemistry which underlies the activity of therelatively small portion of castor oil in relation to the vegetableoilwhich itis used to treat is not explained by the chemical knowledgewhich is available at the present time, and for this reason no theoriesare proffered to explain the changes which take place. From thepractical point of view, in general, the reduction'in acid value isrelated to the quantity of castoroil used for given cooking periods. Be-

cause of this relationship, the acid value is controllable either byusing a given amount of castor oil and adjusting the cooking time, orbetter, ad justing the quantity of castor oil when the cooking time isfixed, the greaterthe amount of castor oil being used, the smaller theacid value for a given cooking period. The change in iodine i valuealso'is controllable in the same manner though the relationship is not somarked. In

most cases the quantity of castor oil should not exceed more than about2 /2% by weight of the varnish oil being treated, if a drying oil orvarnish is desired as the final product. As little as A; of 1% providesvery useful results, and A of 1% most usually is the amount employed.

However, if it is desired to body the oil quickly, without regard to itsdrying properties, then the amount of castor oil may be increased up toabout 15%. When this is done the drying and film forming properties ofthe oil may, nevertheless, be restored to it by the addition of acid,for example, rosin, vegetable and animal fatty acids, such aslinseed-fatty acids and acetic respectively, and even the acids such ashydrochloric and sulphuric. On the other hand, as little as one-eighthpercent of castol oil is capable of producing a substantial reduction,both in the acid value of a given varnish oil, such as linseed duringthe cooking of it, and the cooking time it requires. Thus, the amountsof oastor'oil.

employed are almost trivial in either instance.

On the other hand, the decreasein acid value which accompanies additionof the castor oil is quite rapid. For instance, as a typicalillustration, ADM "Superb linseed oil, and 10% of rosin were heatedtogether with A of 1% of castor oil to cooking temperature. When thecooking'tem perature was reached the acid number was 8.6; ten minuteslater it had dropped to 5.6. In fifteen minutes thereafter the numberwas 5.5, and

in successive quarter hour intervals the values were 5.6, 7, 6.1, 5.9,and then 1.9, respectively. From thislow point the acid value began toin crease. In the absence of the rosin, or other varnish making gums orresins, the acid value remains at, or if free fatty acids are presentdrops gradually toward or to neutral, depending upon the quantity ofcastor oil, and then it again increases in normal fashion. By adjustingthe quantity of castor oil,bearing in mind the time cooking is tocontinue, the acid value can be controlled to a given number at the endof the cook.

The change in acid value, of course, is different for different oils andis influenced by the nature of the oil being cooked, but these factorsare 'un-' derstood by those skilled in the art. 7

By the term castor oil, I mean todesignate the commercial castor oil,for instance, commercial medicinal oil which is available on the market,and castor oil which has been blownwith air. The mono glycerides of thefatty acids also have been found to be similar to castor oil as it isused in the practice of the present invention, though the results arenot so pronounced, and they are, therefore, to be considered as onlypartial equivalents to it. 7

From the commercial point of View, the invention is practiced mostconveniently by the use of what may be termed a control oil. Thiscontrol oil preferably is comprised of a portion of given varnish oiland a quantity of the castor oil which is so adjusted in amount that apredetermined portion of the control oil contains the proper amount ofcastor oil necessary for a treatment of the given batch of varnish oilto be made into varnish. An example of a suitable control oil is asfollows:

EXAMPLE 1 Linseed oil base control oil raw) is added :80 parts ofcommercial medicinal castor oil (such as Bakers AA) and about 715 partsof refined linseed oil, such as ADM superb, in the order stated toaccomplish mutual solubility. Then parts or 15% of this composition, forexample, is used in-conjunction with 85 parts or 85% of the linseedvarnish oil to be cooked. The 15% addition incorporates-about /2 of onepercent of castor oil, 'by weight, in the total batch of varnish oil.This varnish oil then I is cooked in the usual way, but bodies forinstance in 1% hours to a given consistency, as against 7 to 8 hoursrequired for the same consistency in the absence of the castor oil.

In this way, a control oil is obtained which is freely miscible with thevarnish oil in all proportions, and becomes mutually soluble uponheating. The control oil is useful because-it provides a convenientmaterial through which to incorporate the castor oil into the vegetableoil being cooked to make the varnish, and it also is much easier to makeup batches of the control oil for subsequent use than it is to measureout and admix the small quantities of castor oil necessary for thetreatment of a given batch of varnish stock. Moreover, by use of thecontrol oil there is no danger that the castor oil will not beincorporated thoroughly into the oil in the varnish kettle during thecooking phase. In general, the varnish base oil employed in thepreparation of the control oil is preferably of the same vegetableorigin as the varnish oil which the control oil is to be used to treat,though this procedure is not essential. It is generally preferred, forexample, to employ linseed oil in the preparation of a control oil to beused for treating a linseed oil 'to be cooked. But a linseed oil basecontrol oil also may be used 'for treatingsoya or perilla oil. Likewise,by adjusting the concentration of castor oil which is present in thecontrol oil various pro ortions of itmay be used instead of'15% whichhas been disclosed. It 'is not essential, however, that the intermediatestep of preparing the control oil and then using it be practiced sincethe castor oil can be incorporated directly into the oil in the varnishkettle, if desired. An example of the alternative procedure is asfollows:

EXAMPLE 2 Refined linseed varnish oil, such as ADM Superb or SpencerKellogg's Superior is cooked with one-fourth of 1% of castor oil, forexample, Bakers AA, for 1 hours to the same consistency that wouldrequire 7 to 8 hours cooking time, the castor oil preferably being addedwhen cooking temperature has been reached.

For the most part, it is preferable to incorporate the castor oil whenvarnish oil in the kettle has been brought to cooking temperature andpartially cooked. At the higher temperature, there is greatermiscibility of the components and less danger of improper incorporation,There is also more prompt chemical activity when this is done.

The manner in which the varnishes and printing ink bases are made at thepresent time is well understood in the art, and the present invention isadapted to be used in accordance with these recognized practices, aswell as in accordance with specialized techniques.

The following examples will assist those skilled in the art in theapplication of the principles of the invention to the industry.

EXAMPLE '3 In place of thecontrol oil of Example 1, the

control oil maybe as follows:

136 parts of whiteheavy bodied raw, 11.3 parts Bakers #16 castor oil(blown oil) and 533 parts printing ink linseed (e. g. ADM special raw)are mixed together in the order named. 15% of this base or control oilis added to of the varnish oil to be kettle cooked. The varnishesresulting from cooking with this control oil are especially useful inprinting ink formulations, due

to the freedom from livering which is provided.

EXAMPLE 4 Instead of using the control oil above, nonlivering printinginks are made adding about one-fourth of 1%, by weight, blown castor oilto the batch of printing ink oil (for example, special raw).

EXAMPLE 5 .A typical synthetic resin varnish may be made by using 25parts pale Bakelite resins (Bakelite resin BR. 254 for example) 4 partsof water white rosin, parts linseed oil (Superb or Superior, forexample) are mixed and heated to 575 F. within thirty minutes, at whichtime one-fourth of 1%, by weight, of castor oil is added. Thetemperature is held for forty-five minutes. The body is quite heavy andmay be thinned with 40-50% volatile solvent with addition of T japandrier. The varnish dries in air in four hours and is useful as anoutside spar or aircraft varnish. The varnish has better adhesion togalvanized iron than a similar varnish made in the conventional manner.In the absence of the castor oil, three hours cooking time is required,after the cooking temperature has been reached, to obtain the same body,but this varnish is very dark in color (due to the long cooking) and thevarnish will not dry in the air. Perilla and oiticica oils respond totreatment and may be handled in the same way as linseed with dueattention to the cooking temperatures which are used in the formulationof these oils.

EXAMPLE 6 EXAMPLE 7 To make an outside spar type varnish of 50 gallonlength using phenol formaldehyde resin the procedure is as follows:

The oil is made of one-half soybean oil and one-half perilla oil. 90parts of this oil, 4 parts of water white rosin and 25 parts of thephenol formaldehyde resin, for instance, Bakelite resin BR 254, areadmixed together and the oil is heated to 575 F., and at this time, .2part of castor oil, for example, Bakers AA are added, the castor oilamounting to one-fourth of 1% of the oil. The cooking temperature is runto 575 F. in thirty minutes and then held for body. The varnish isthinned with toluol to 40% volatile matter and driers added.

' perilla of the previous example.

cedure is the same.

EXAMPLE. 8

A. varnish similar to th'e varnish of Example '7 is made by using anadmixture of 50% linseed oil and 50% perilla oil instead of soybean andThe other pro- I I EXAMPLE 9 v A, varnish similar to'the varnishes ofExamples 7 and'8 is made by using the same procedureof Example 7 withthe exception that the oil is made by using 50% of cottonseed oil with50% of perilla oil and 1% of castor oil; for example, Bakers AA is usedin place of one-fourth of 1%.

All cottonseed oil may be employed in place of the mixture of cottonseedand perilla, soybean and linseed, by varying the proportioniof castoroil, though the employment of a faster drying oil in conjunction withthe cottonseed is desirable to accelerate the drying properties.

The vehicles which are used -in the printing ink manufacture, when madein accordance with the present invention, have several importantadvantages.

In the first place they are free of the tendency to liver or form stiffgels when used in conjunction with the pigments that have a tendency tocause this chemical action. For instance, with peacock blue and chromelemon and prussian orange,,the most notablejoifenders tending tocauselivering,,the inks madelin accordance With the present invention werefree from .livering after an extended storage period, while liveringtakes place .in conventional ink varnishes otherwise treated in the sameway. The'varnishes made in this manner also have much better wettingproperties in relation to the pigment and this explains in part thenonlivering tendencies, .while the control of the acid value alsoassists inthe formulation of quality materials at low cost. .Theprevention of this actionis important in the industry because itheretofore has been necessary for the printers to use the inks shortlyafterthey were received, since livering would have occurred had theybeen stored.

In regard to physical properties the varnishes which are made throughthe practice .of'this invention are superior to the varnishes whichotherwise would be made in the conventional manner in several importantrespects. Thefilms from the linseed oil varnishes, for example, exhibitthe properties of flexibility, toughness, durability and drying time ofthe typical Chinawood oil varnishes available-at present. Thesevarnishes, moreover, when subjected to ultraviolet light show excellentdurability. They withstandthe caustic soda tests and the boilingwatertest to a marked degree. Also, in relation to adhesion, flexibility andbending and elasticity, the films of varnishes made in accordance-withthe present invention are better than similar films made without itspractice. The'films do not exhibit the usual tendency to check in-agaseous atmosphere and do 'not possess-the undesirable taste or odor ofthe typical China-wood oil varnishes. Y. w

Having described my invention, I claim:

1. The method of making a'varnish of linseed'oil, which approximates theproperties of a China-wood oil'varnish, which comprises cooking ence ofapproximately A; of 1% to -2 'of r-castor oil at varnish cookingtemperature until the oil is polymerized. 1 r I? 4. The method of makinga varnish; which comprises, cooking perilla varnish oil in thepresenceof approximately of 1% to 2 /2% of castor .oil at varnish cookingtemperature until the varnish attains the desired body. I

- 5. The method of making a varnish which comprises cooking an oilselected fromthe group consisting of soybean=.oil, linseed. oil, perillaoil,

fand cottonseed oil in thepresence of approximately 0f 1% ,t0, 2 /2% ofcastor oil., .I

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